BRAIN MACROPHAGES - INVOLVEMENT IN MORPHOLOGICAL-CHANGES AND DEATH OF NEURONAL CELLS

Microglial cells in the developing central nervous system transiently display a macrophagic phenotype. These brain macrophages can also appear into the adult parenchyma following various tissue injuries or during neuroinflammatory and neurodegenerative diseases. Brain macrophages are involved in tissue degradation or remodeling. This paper reviews recent data related to the influence of these cells on the morphology and the survival of neurons. In vivo observations support the notion that brain macrophages can induce neuronal death or morphological regression of axonal arbors. Moreover, ex vivo cultured brain macrophages, derived from immature rat brain, produce reactive oxygen intermediates which account for deleterious effects on neurons growing in their vicinity. Conversely, studies focused on the nerve growth factor (NGF) production by nervous cells suggest mechanisms whereby brain macrophages could favour survival and growth of central neurons.